Development of a dual conical spouted bed system for heat integration purposes

• A dual spouted bed system has been developed for allothermal processes.
• The fountain–annulus configuration is the best one for the interconnection pipes.
• Solid circulation rate and so heat transfer may be varied in a wide range.
• Stable solid circulation is attained without any mechanical device like valves.
• Low gas bypassing augurs well for the scale up of pyrolysis plants.

This paper describes preliminary studies carried out to develop a system made up of two interconnected spouted beds for heat integration in highly endothermic processes, such as pyrolysis and gasification. Four different configurations of a dual spouted bed system have been studied depending on the location of the feeding and discharging points in the interconnection pipes, i.e., annulus–annulus, annulus–spout, fountain–spout and fountain–annulus. Fountain–annulus configuration has been determined to be the optimum option based on its stability, solid transfer rate (around 120 kg h− 1) and gas bypassing from one contactor to the other (below 1.5%). Once the optimum system has been established, the viability of the dual spouted bed system has been assessed for heat integration in the biomass pyrolysis, with the minimum temperature difference between the pyrolyser and combustor being 280 °C for attaining allothermal operation. Furthermore, studies have been carried out on the solid circulation rate (energy balance), gas bypassing from one contactor to the other and system stability against different perturbations, which have allowed determining the optimum configuration

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